Use-dependent dendritic regrowth is limited after unilateral controlled cortical impact to the forelimb sensorimotor cortex

Compensatory neural plasticity occurs in both hemispheres following unilateral cortical damage incurred by seizures, stroke, and focal lesions. Plasticity is thought to play a role in recovery of function, and is important for the utility of rehabilitation strategies. Such effects have not been well described in models of traumatic brain injury (TBI). We examined changes in immunoreactivity for neural structural and plasticity-relevant proteins in the area surrounding a controlled cortical impact (CCI) to the forelimb sensorimotor cortex (FL-SMC), and in the contralateral homotopic cortex over time (3-28 days). CCI resulted in considerable motor deficits in the forelimb contralateral to injury, and increased reliance on the ipsilateral forelimb. The density of dendritic processes, visualized with immunostaining for microtubule-associated protein-2 (MAP-2), were bilaterally decreased at all time points. Synaptophysin (SYN) immunoreactivity increased transiently in the injured hemisphere, but this reflected an atypical labeling pattern, and it was unchanged in the contralateral hemisphere compared to uninjured controls. The lack of compensatory neuronal structural plasticity in the contralateral homotopic cortex, despite behavioral asymmetries, is in contrast to previous findings in stroke models. In the cortex surrounding the injury (but not the contralateral cortex), decreases in dendrites were accompanied by neurodegeneration, as indicated by Fluoro-Jade B (FJB) staining, and increased expression of the growth-inhibitory protein Nogo-A. These studies indicate that, following unilateral CCI, the cortex undergoes neuronal structural degradation in both hemispheres out to 28 days post-injury, which may be indicative of compromised compensatory plasticity. This is likely to be an important consideration in designing therapeutic strategies aimed at enhancing plasticity following TBI.     

Early, patient-initiated treatment of herpes labialis with topical 10% acyclovir.

To determine whether topical acyclovir in polyethylene glycol could reduce the severity of herpes simplex labialis if applied immediately after onset of a recurrence, 10% acyclovir in polyethylene glycol ointment or polyethylene glycol alone was prospectively dispensed to 352 patients in a double-blind, randomized trial. Sixty-nine subjects initiated treatment in the prodrome (57%) or erythema (43%) stage and were followed by clinical and virological criteria. The healing time (6.0 days), maximum lesion area (42 mm2), vesicle or ulcer formation (91%), and maximum lesion virus titer (4.8 log10 PFU) in the drug recipients were not reduced in comparison with those who received the vehicle (5.2 days, 30 mm2, 75%, and 4.5 log10 PFU, respectively). Topical acyclovir in polyethylene glycol was ineffective for the treatment of herpes labialis despite an optimum therapeutic opportunity.     

Self-efficacy moderates the impact of stressful events on headache

A positive correlation between the frequency of headache and the frequency of stressful events was demonstrated in a sample of 114 headache sufferers. The strength of this relationship was shown to be moderated by the level of self-efficacy, defined as the individual's perceived capacity to exercise self-control over their cognitive, behavioral, and affective responses to stressful events. The relationship between stressful events and headache was strongest for subjects low in self-efficacy and became progressively weaker as self-efficacy increased. It was concluded that self-efficacy may be an important psychological resource buffering the impact of stress on the frequency of headache. Theoretical implications and indications for further research are discussed.     

Chronic ethanol consumption by C57BL/6 mice promotes tolerance to its interoceptive cues and increases extracellular dopamine, an effect blocked by naltrexone

BACKGROUND: C57BL/6 (B6) mice voluntarily consume ethanol. Although preingestive factors might be accountable, the fact that B6 mice voluntarily consume sufficient ethanol to set the conditions for an ethanol-deprivation effect suggest that post-ingestive pharmacological induced changes also occur. In this study, we determined the amounts of ethanol voluntarily consumed by B6 mice and associated blood ethanol levels (BEL), the effects of this consumption on extracellular dopamine (DA) and how this was altered by naltrexone, as well as on its interoceptive discriminative cues. METHODS: In experiment 1, the amounts of 12% ethanol consumed at 2, 4, and 6 hr into the active phase of the circadian cycle and associated BEL were determined. In experiment 2, dialysate samples were collected for 1 hr to establish basal DA levels. Mice were then injected with saline or naltrexone (6 mg/kg) and given access to water and 12% ethanol or to water only, and samples were collected at 20-min intervals for the next 2 hr. In experiment 3, mice were trained to discriminate ethanol's interoceptive cues via operant techniques, and half were given 3 weeks access to ethanol and water, the other half water only. Ethanol-consuming and water control mice were again tested for their ability to discriminate the drug's interoceptive cues. RESULTS: Mice ingested nearly 6 g/kg of ethanol and attained BEL near 100 mg/100 mL by 6 hr into the active phase. Ethanol intake at 2-hr into the dark phase was approximately 2.5 g/kg, and increased DA to approximately 100% above basal levels. Naltrexone reduced ethanol consumption and blocked the DA increase. Ethanol consumption for 3 weeks attenuated its discriminative cues. CONCLUSIONS: B6 mice voluntarily consume sufficient ethanol (1) to produce intoxicating BEL; (2) to increase DA levels in nucleus accumbens, an effect blocked by naltrexone; and (3) to attenuate its discriminative cues.     

Feasibility of spirometry and reversibility testing for the identification of patients with chronic obstructive pulmonary disease on asthma registers in general practice

There is renewed interest in the diagnosis of chronic obstructive pulmonary disease (COPD) within primary care. Primary care physicians have difficulty distinguishing asthma from COPD. We tested the feasibility of using spirometry and if appropriate, reversibility testing, to identify patients with COPD on asthma registers in primary care. We carried out a cross-sectional study in three inner-city group practices in east London. Three hundred and twenty-eight patients aged 50 years and over on practice asthma registers were invited to attend for spirometry and, if appropriate, a trial of oral corticosteroids. The main outcome measures were: feasibility of carrying out spirometry; lung function; severity of COPD; prior diagnosis of COPD; response to a corticosteroid trial; quality of life. One hundred and sixty-eight of 328 (51%) patients attended for spirometry. According to British Thoracic Society criteria, 58 (34%) patients had normal spirometry at the time of assessment; 40 (24%) had active asthma and 57 (34%) had COPD. Thirteen patients (8%) were unable to perform spirometry. Of 57 patients with COPD 30 (53%) had mild, 15 (26%) had moderate and 12 (21%) had severe disease. Twenty-three of 57 (40%) patients with COPD on spirometry had this diagnosis recorded prior to the study. New diagnoses of COPD were more likely in those with mild or moderate disease (P<0.05). Twenty-three of 57 (40%) patients with COPD completed a corticosteroid trial: one showed significant reversibility of lung function. Spirometry was feasible and helped identify patients with COPD on asthma registers in these inner-city practices. Patients aged 50 years and over on asthma registers had a wide spectrum of lung function with considerable diagnostic misclassification. Some patients with normal lung function when tested may have had well controlled asthma. New diagnoses of COPD were mainly in those with mild or moderate disease.